W. R. Huber, J.A.C.S. 77, 112-116 (1955) discloses a method (p. 112) for making racemic mixtures of aminoacyl glycerides by treating an alpha-halogen ester with sodium azide to form an alpha-azido ester, which was then saponified to give the alpha-azido acid. This acid was then converted to the acid chloride with thionyl chloride, which was, in turn, reacted with glycerol, or a monoglyceride, or a diglyceride, to form a tri-, di-, or mono-alpha-azidoacyl glyceride. The formation of the glyceride was accomplished via a ketene intermediate and yielded a racemic mixture. The formal glyceride was hydrogenated to convert the azido group to an amino group. On p. 113, Col. 1, the paper states that an alpha-aminoacyl glyceride was treated with an alpha-azidoacryl chloride "to yield an alpha-azido-acylaminoacyl glyceride which, on hydrogenation, yielded the `dipeptide-glyceride`." The relevant reactions are considered to be: ##STR1## In the Huber paper R is identified as a long chain fatty residue, such as laurin, palmitin, stearin, etc. Note that the ester moiety (glyceryl) is retained intact and is not converted to amide. My ester group, on the other hand, reacts with and is replaced by amine to form an amide group.
In the Huber synthesis, the ester moiety (glyceryl) is retained in tact and is not converted to an amide, as presently achieved. Further, Huber's synthesis provides a product which is a racemic mixture and is not capable of achieving an optically active product nor one which is substantially free of one enantiomer as is possible by the present invention.